Query Loop Block: Set depth limit

[Drivingralle]

What problem does this address?

While setting up a Query-Loop block inside the footer to list posts from a CPT, the query is fetching post from all levels. I want to limit the query to just the top level.

If the posts would be children of a singular post I could use the parents field. But for top level post don't have a parent and there is no way to set the parents field to 0.
A custom WP_query in classic world can do this.
Also changing the query of the Query block via a php filter works.

What is your proposed solution?

Similar to my suggestion in #54461 it would be possible to give the parents field an option to set it to no-parent/top-level/0.

Alternatively and way more complicated:
Add an option to the filter panel to set the depth of the query to X levels deep.
This setting could be combined with the parents field. Fetching post at are children of "post-id" or grand-children X levels down.

[Mamaduka]

But for top level post don't have a parent and there is no way to set the parents field to 0.

It is not ideal, but you can do this by setting the "parents":[0] via Code Editor. But I agree there should be easier way to set this.

Add an option to the filter panel to set the depth of the query to X levels deep.
This setting could be combined with the parents field. Fetching post at are children of "post-id" or grand-children X levels down.

This might require REST API changes first. I don't remember if similar queries are supported.

[Drivingralle]

Interesting idea to do it via the code view.

Sadly I seam not to work fully. Inside the site editor it looks good. But in the frontend it doesn't work. The query in frontend seam to have some extra validation.

Here in a video:
https://cloudup.com/cXMFW3Rb1r5

Outside the video I tried to filter by "Sample page". That works.

[Mamaduka]

I think it is due to this line in the build_query_vars_from_query_block method - https://github.com/WordPress/wordpress-develop/blob/d2a7bee9a6201f0276492ff29afd8c509480d266/src/wp-includes/blocks.php#L2594. The array_filter will remove all "empty" values, including 0, but it's valid value for parents.

[Mamaduka]

@Drivingralle, create PR that should resolve "parents":[0] allowing programmatically creation top-level item queries - #68983.

The next step would be to provide a UI and allow users settings this value. Requesting feedback because I'm unsure what's the best solution here.

One option could be to have a static token, something like "No parent", which maps to 0.

Screenshot

[Mamaduka]

@Drivingralle, the #68983 is merged now. You should be able to create similar queries programmatically.

[kjnanda]

I tested this PR and looks like it does not take the argument that we set as value in Parent Filter. I followed the testing instruction shared in the PR but looks like it is not working.

@Mamaduka can you please share the visual of fix? 🙇‍♀

[Mamaduka]

@kjnanda, #68983 only partially solves the issue by allowing programmatically setting "parents":[0], as noted in my previous comment and the PR; it doesn't provide the UI for it. The PR contains an example Query markup you could use for testing.

Regarding UI - The Parent filter will be updated once there's a good design proposal.

[kjnanda]

Okay, got it!

Thank you for the prompt response! 🙌🏻

[Mamaduka]

Moving this out of the WP 6.8 project board. We could resume working on this enhancement once there's a design proposal. Meanwhile, consumers can programmatically set paret: 0.